New soft gelatin capsules highly protected against the degradation of the active ingredient contained therein and highly resistant to hydration are described. The capsular wall is characterized by containing hydroxypropyl beta cyclodextrin in low quantity with respect to the weight of the wall and sub-stoichiometric with respect to that necessary for complexing the drug contained within the capsule. The new capsules are storage-stable, avoid the development of active ingredient by-products and maintain a high weight constancy, i.e. low hygroscopy.
